A doctor who runs the ER where James Gandolfini was taken before he was pronounced dead says there are no suspicious factors, such as alcohol, but the statement appears premature -- especially with respect to any drugs that might have been in the actor's system.

Professor Claudio Modini, the chief ER doc, says it looks like a heart attack, adding it was "probably a natural cause of death, myocardial infarction."

Gandolfini had acknowledged he had been addicted to cocaine and booze, and substance abuse played a part in his 2002 divorce.

As for the professor's tentative conclusion, it's premature to know if drugs or alcohol were a factor.  It's also unclear what -- if any -- toxicology tests will be performed on Gandolfini's body.

As we previously reported, Gandolfini died Wednesday in Italy while on vacation with his son. He had been staying at the Boscolo Hotel Exedra in Rome (pictured below).